Dennis Rodman probably liked President Trump enough to try to do it for him while in office. Or just maybe President Trump knows that one must know his enemies. Maybe President Trump knew that the President of North Korea favored Dennis Rodman.

President Trump is not a former lawyer. He is a former businessman with lots of knowledge in getting things done. How many lawyers have you known to sit on something and never accomplish much?

I seriously doubt either had a trickle of effect, N. Korea probably realized any edge they had in holding him now that he is non functioning, in a coma would be of little value to them and actually cost them for his care, meager as it was
the world sees it as charitable but the N.Koreans are a long way from being charitable
if anyone had anything to do with it it was probably Dennis Rodman

Obama had no experience talking to world leaders. Mr. Trump does and used back channels probably. Obama had to be advised by different people before he took action. Mr. Trump thinks and decides for himself.